public net/minecraft/server/WorldLoader loadAndReplaceLayer(Lnet/minecraft/server/packs/resources/ResourceManager;Lnet/minecraft/core/LayeredRegistryAccess;Lnet/minecraft/server/RegistryLayer;Ljava/util/List;)Lnet/minecraft/core/LayeredRegistryAccess;

# for auto-marking experimental stuff
public net/minecraft/core/RegistrySetBuilder entries
public net/minecraft/core/RegistrySetBuilder$RegistryStub
public net/minecraft/data/registries/UpdateOneTwentyOneRegistries BUILDER